ABCG2 and cancer: Moreover, other multidrug resistant cancer cells such as BCRP-overexpressing S1-MI-80 cells, HEK293/ABCG2-482-R2 cells and HEK293/ABCG2-482-T7 cells, MRP1-overexpressing HL60/adr cells and their corresponding parental cells were also confirmed (Fig. 1B-C) and used in the following experiments.